First thing you need is either...
...a holding tank or a treatment device. This isn't a future probject, you cannot legally flush your toilet directly overboard within 3 miles of the US coastline. That means 3 miles out to sea, not just 3 miles from the nearest shorel All of RI and much of MA is "no discharge"--Nantucket, Marthas Vineyard, most if not all of Buzzards Bay...so even with a treatment device--i.e. Lectra/San--you'd still need a holding tank too for use in those waters, although treatment devices are legal in LI Sound. As for which toilet, you can't have fresh water flush without power...because only electric toilets are available with a fresh water flush option--it requires a solenoid. However, the good news is, fresh water flush uses a fraction of the power that raw water toilets needs, and also use a fraction of the flush water.I think with two children aboard, your best option is a Raritan Crown II, which is a macerating electric toilet. Go with the fresh water flush option and also the wall touch pad flush option which offers a choice of 4 flush options (you can just tell the kids to push "this one")--standard flush, which uses about 3 quarts of water...low water flush, which uses about a quart, dry, which just empties the bowl...and one that flushes as long as you keep your finger on it. West, B/US, Defender and everyone else carries it....shop the best price.Check it out on the Raritan website at http;//www.raritaneng.comIf manual is more what you had in mind; the Cricket (also Raritan) is prob'ly your best bet...if it weren't for the kids, I'd suggest the PH II. However, NOT the PHE II...it's electric, but all the motor does is replace the pump handle--for only about $100 less than you can buy the Crown II.As for your holding tank...call Ronco Plastics. 714-259-1385. Their tanks are far superior--better quality, MUCH thicker walls--than anything in the catalogs, plus they offer more than 400 different shapes and sizes--and you get to spec where the fittings go. In fact, they've made tanks for Catalina for years, but I don't like where Catlina puts holding tanks, so I don't recommend you just order the OEM replacement. And before you do ANYthing, read the articles in the Head Mistress forum Reference Library so you'll know what TO do. It's so much easier and cheaper to do it right the first time than it is to do anything over.